Rotary device for application of a protective compound coating on the inner wall of conduits



Nov. 26, 1963 A; C. CURTIS 3,112,227

ROTARY DEVICE FOR APPLICATION OF A PROTECTIVE COMPOUND COATING ON THE INNER WALL OF CONDUITS Filed June '7, 1960 ARVEL C. CURTIS INVENTOR.

United States Patent 3,112,227 ROTARY DEVICE FOR APPMCATIS'N @F A PRO- TECTIVE COMPOUND CUA'IING ON THE INNER WALL 0F CONDUIIS Arvel C. Curtis, Dallas, Tex, assignor to Pipelife Corporation, Dallas, 'Iex. Filed June 7, was, Ser. No. 34,464 3 Claims. (Cl. 118-408) The invention relates to a rotary device especially designed for use in the application of a protective coating on the inner wall of a length of pipe, in the yard, prior to its being assembled to form a pipe-line serving for the transmission of fluid or gaseous materials.

It is now a well established practice to apply a protective coating on the inner wall of pipes, for reasons which are well known to those skilled in the art. However, the application of such a coating, in the industry, has not been efficient.

The main object of this invention is to provide an assembly which can be mechanically operated, with a maximum of efficiency, for the application of a protective compound to the interior of a length of pipe.

Another object of this invention is to provide applicators, the construction of which improves the ease of application of an effective coating.

One more object of this invention is to provide a helix or spiral type applicator, the construction of which provides concave and convex points; the concave points serving as reservoirs for the protective compound and the convex points serving as spreaders and applicators.

A further object of this invention is to provide a spiral applicator constructed of neoprene and the molding of which embodies in it a hollow metallic shaft which serves as a combination of conduit and reservoir for the coating compound.

Yet a further object of this invention is to provide an assembly made of three essential parts, namely, a central body, a left hand screw applicator, and a right hand screw applicator. When the device is rotated, the left hand screw applicator and the right hand screw applicator both have a centrifugal effect, compressing the compound toward the center of the device and thus forming a combination of container and applicator.

Other objects and advantages of the invention will become clearer from the more detailed description of the invention, the preferred embodiment of which is illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevation View of an applicator according to the invention;

FIGURE 2 is a partially sectional view on the line 22 of FIG. 1; and

FIGURE 3 is a sectional view of the central core on the line 3-3 of FIG. 2.

The central part 2 of the device, shown in section in FIGURE 3, is a combination of a distributor and primary spreader for the compound to be applied on the interior pipe wall. It is constructed of a resilient material, such as neoprene, the core of which embodies a hollow metallic shaft 4 which serves as a combination of conduit and reservoir for said compound. Each end of shaft 4 has a female thread to receive and hold the central pipe 6 of a spiral applicator 8 on both ends. The body of the central part 2 has a central portion the width of which is approximately one half of that of the conduit to be coated, and four blades Ill located at 90 apart, extending to the full diameter of the conduit to be coated. The combination of these four blades 1i) form an equilateral, equidistant and equiangular cross; the four concave portions thus formed serve as chambers to contain and distribute the compound which is admitted into these chambers from the central, hollow, shaft 4 through four holes 12, located degrees apart and drilled through the surface of the central part of the shaft 4.

The two separate applicators 8 include one with a left hand screw and the other with a right hand screw construction. As illustrated in FIGURE 1, the screw section applicators 8 are spiraled in opposite senses and are illustrated as having equal pitch. The applicator sections 8 are made 'of resilient material such as neoprene. The resilient material is molded onto a hollow elongated member 14, having three sections. As shown in FIG- URE 2, the upper section has external male threads extending beyond the molded rubber portion. The upper section is secured to the central section. A similar connection is made between the lower section and the central section so that the center portion has female threads on each side of the central body 2.

In use, at one end of this assembly is connected, by a threaded coupling engaged in the female threads of one of the applicators, a tubular member 18 of appropriate diameter and length in accordance with the diameter and length of the conduit to be coated. The elongated tubular member serves as a conduit to bring the coating compound, under pressure and from an outside source, to the distribution area at the center of the central body and, simultaneously, serves as a driving shaft to impart a rotary motion to the applicator assembly at a predetermined rate of revolution from an outside source of power.

These spiral applicators can be characterized as being of the Archimedean screw type, with deep, wide, rounded grooves and flat thin ridges or ribs; the outer applicator having a right hand thread and the inner applicator having a left hand thread. Consequently, when the whole device is rotated in a clockwise direction as viewed from the driving end, the centrifugal effect of left and right hand spirals assures :a constant volume of compound in each concave portion of the applicators. The amount of centrifugal pressure thus created is proportionate to the controllable speed of rotation at which the device is turning.

While I have described herein embodiment of my invention, I wish it to be understood that I do not intend to limit myself thereby except within the scope of the claims hereto or hereinafter appended.

I claim:

1. Apparatus for coating the interior of a pipe comprising an elongated assembly of three parts forming two end zones and a central chamber section, each of said two end zones having resilient spiral ribs wherein the pitches of the spiral ribs in said two zones are opposite in sense and are of dimension as to engage the inner Walls of a pipe and said central chamber section having axially extending wiper blades, means forming a flow channel extending from one end of said elongated assembly to said central chamber section between said end zones by which fluid can be supplied and deposited to said central chamber section for application by said spiral ribs to the interior wall of said pipe 'while rotating said elongated assembly.

2. Apparatus for coating the interior of a pipe which is accessible from one end of said pipe which comprises a hollow elongated member of three parts characterized by end sections having spiral ribs wherein the pitch of the spiral ribs on said end sections is substantially equal but of opposite sense and a central chamber section having radial axially extending wiper blade means, a hollow conduit extending through at least one of said end sections to said central chamber section and adapted to be connected to a power source for rotating said elongated member and for delivering through the hollow core into said central chamber section a coating material which is maintained substantially entirely in the area between said spiral ribs while turning said elongated member in a direction which urges the coating material toward the center of said elongated member.

3. An apparatus for coating the interior of a pipe comprising two end sections and a central section coupled together, each of the end sections having resilient spiral ribs wherein the pitches of the spiral ribs on said ends are opposite in sense and are of dimension to engage the inner wall of a pipe, ribs on said central section extending parallel to the axis of said apparatus for forming with the interior wall of the pipe a plurality of chambers of substantially equal size, means forming a flow channel References Cited in the file of this patent UNITED STATES PATENTS 2,107,738 Perkins Dec. 21, 1937 2,480,358 Curtis et al Aug. 30, 1949 2,517,780 Frank Aug. 8, 1950 2,670,991 Perkins Mar. 2, 1954 

3. AN APPARATUS FOR COATING THE INTERIOR OF A PIPE COMPRISING TWO END SECTIONS AND A CENTRAL SECTION COUPLED TOGETHER, EACH OF THE END SECTIONS HAVING RESILIENT SPIRAL RIBS WHEREIN THE PITCHES OF THE SPIRAL RIBS ON SAID ENDS ARE OPPOSITE IN SENSE AND ARE OF DIMENSION TO ENGAGE THE INNER WALL OF A PIPE, RIBS ON SAID CENTRAL SECTION EXTENDING PARALLEL TO THE AXIS OF SAID APPARATUS FOR FORMING WITH THE INTERIOR WALL OF THE PIPE A PLURALITY OF CHAMBERS OF SUBSTANTIALLY EQUAL SIZE, MEANS FORMING A FLOW CHANNEL EXTENDING FROM ONE END OF SAID APPARATUS TO SAID CENTRAL SECTION AND HAVING OUTLETS LEADING INTO EACH OF SAID CHAMBERS BY WHICH FLUID CAN BE SUPPLIED AND DEPOSITED IN 